Irradiation appliance

ABSTRACT

The invention relates to a radiation device that includes a housing, a light-emitting unit and a light-absorbing unit which is provided with an inlet opening and a reflector element. The reflector element extends across the entire distance between the light-emitting unit and the inlet opening of the light-absorbing unit.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 10/514,034, filed May 21, 2003, which is a U.S. National StageApplication of PCT/EP2003/005316, filed May 21, 2003, which claimspriority from German Application No. 10222828.0, filed May 21, 2002.

BACKGROUND AND SUMMARY OF THE INVENTION

JP 9-10238 A discloses a dental irradiation appliance, in which an arraycomposed of light-emitting diodes is arranged on the cap surface of anoptically conductive body which is in the form of a spherical sector andis composed of quartz or plastic, and whose tip merges into an opticalwaveguide rod. The beams from the light-emitting diodes are focused bythe optically conductive body by reflection on the conical wall, and areintroduced into the optical waveguide rod.

WO-97/36552 A discloses a further dental irradiation appliance, in whicha planar array composed of light-emitting diodes with parallel opticalaxes is opposite the curved inlet surface of an optically conductivebody, which is once again conical. This condenser is coupled on theoutput side to an optical waveguide, and may be filled with an opticallytransparent liquid.

Apart from the fact that conical optically conducting bodies such asthese and as described in the documents cited above, or else asdescribed in WO 99/16136 (FIG. 4), are complex to manufacture andincrease the weight of the appliance, they also cause considerableradiation losses. This is because, whenever a light beam is reflected onthe conical wall of the optically conductive body, the beam is deflectedthrough twice the cone angle from the optical axis. Even after a smallnumber of reflections, this leads to the angle for total internalreflection in the optical waveguide being exceeded, and in the beamsemerging from the optical waveguide, or, if the optical waveguide ismirrored, even in the direction of the beams being rotated, and thus notbeing passed to the light outlet opening, but being passed back to thelight inlet opening.

Arrangements such as these thus function only for that component of thelight injected from the LEDs whose beams are tilted only in a verynarrow angle range with respect to the optical axis. The majority of thelight emitted from the LEDs can thus not be used to illuminate thetreatment area, since the light cones with which LEDs emit lightnormally have a considerably greater aperture angle.

WO-99/16136 A (FIG. 6) also discloses an appliance having amultiple-conical optically conductive body, in which two or more annularlight inlet areas precede a circular light inlet area. In this case, thelight is guided by the multiple-conical optically conductive body fromthe first circular light inlet area into the central area between thefirst annular light inlet area. Together with the light from the LEDs,which irradiate this light inlet opening arranged in an annular shape,it is now passed into the center of a further combination of an LED ringand an annular inlet area. The light gathered in this way is now passedto an outlet opening through the optical waveguide, whose furtherprofile is once again conical.

In this arrangement as well, and for the reasons mentioned above, only asmall proportion of the beams which are emitted from the LEDs reach thelight outlet opening, and hence the point to be irradiated. As a resultof two or more conical optically conducting bodies being arranged onebehind the other, the efficiency of the areas which are located furthestaway from the outlet opening is reduced even further than that in thecase of a single-conical condenser. Furthermore, it is even moredifficult and expensive to manufacture the multiple-conical opticalwaveguide.

Other embodiments of irradiation appliances which are based on LEDs andmanage without a conical optically conductive body, and hence withoutthe disadvantages associated with them, are also known. For example, JP08-141001 A (FIG. 1) and WO-99/35995 A (FIG. 4) propose opticalconvergent lenses for focusing the beams emitted from an LED array, andfor focusing them onto the light inlet area of an optical waveguide.

In this case, all of the beams which are emitted from the individualLEDs in the direction of the convergent lens are deflected. However, thedeflection to the desired direction and the focusing of the beams onceagain take place only for that proportion of the beams which strike theconvergent lens essentially parallel, or differ slightly from thisdirection depending on the size of the light inlet area. A considerableproportion of the beams cannot be passed from the convergent lens to thelight inlet opening, and this proportion is thus lost for theirradiation of the treatment point.

In the arrangement which is illustrated in FIG. 1 of WO-99/35995 A, 9LEDs are aligned individually in the direction of one optical waveguide,in which case it has been possible to observe only partial hardening ofa light-hardening sample. This is a result of inadequate light power asa consequence of non-optimum light injection, as well as the smallnumber of LEDs which can be used with the described arrangement.

In a further appliance, which is described in WO-00/13608 A, and isbased on a similar arrangement of the LEDs with respect to the lightinlet opening of an optical waveguide, the light power is increasedfirstly by using a conical optical waveguide, and secondly by applying amultiple of the nominal operating current to the diodes. The conicaloptical waveguide results in the problems which have already beendescribed further above.

The high operating currents have the disadvantage that the heat lossesin the LEDs increase more than proportionally and are large, so that theappliance becomes warm after a short time, and cannot be used for alengthy time, until it has cooled down. Furthermore, the life of LEDs isgreatly decreased by the high operating currents. This is evident from acontinuous decrease in the light power over the course of time.

The arrangements of LEDs in the form of individual semiconductor chips,as proposed in WO-99/35995 A, WO 02/11640 A2 or EP 0 879 582 A, on acommon substrate are not without their problems either, since theindividual elements heat one another up, thus once again limiting thelight intensity and/or the life. Furthermore, it is considerably morecomplex and expensive to produce arrangements such as these, since it isnot possible to use standard components, which are also mechanicallyeasy to handle.

A further irradiation appliance having two or more LEDs is disclosed inWO-01/19280 A. The LEDS are arranged in a specific manner on a number oflevels in order to allow the light that is produced to be injected asadvantageously as possible into an optical waveguide.

All of the above appliances have the common feature that the achievablelight powers are limited by the LED arrangements described there.

In order to further increase the light power, an array comprising alarge number of individual LEDs is proposed. However, as the number ofindividual LEDs increases, it becomes ever more difficult to gathertheir emitted light. By way of example, WO 02/11640 A2 discloses afocusing lens in addition to a reflector, in order to focus the beamsfrom the LED array in order that they can be injected into an opticalwaveguide.

Furthermore, as the number of LEDs rises, the space required, theelectrical power required and the electrical heat losses which have tobe dissipated from the LEDs in order to allow a long life also increase.For the reasons stated, it would be desirable to manage as far aspossible with only one individual LED, and this would have a positiveinfluence on the production costs.

In principle, it is possible to use high-power LEDs to achieve thisobject, which can emit far greater light power levels than conventionalLEDs. However, the light that is produced must be gathered with as fewlosses as possible in this case as well and, for example, must be passedby means of an optical waveguide to the treatment point, since theperformance of an LED array can otherwise not be achieved.

Irradiation appliances which are equipped with only one LED have beenproposed, for example, in the documents U.S. Pat. No. 6,318,996 B1 andWO 01/64129 A1. WO 01/64129 proposes that such high currents be appliedto the LED that the life is shorter than 10 hours since, otherwise, itis not possible to achieve sufficient radiation power.

In U.S. Pat. No. 6,318,996, an intensity of only between 25 and about 38mW/cm² is achieved with a single LED. Values such as these arerelatively low for irradiation appliances for hardening dentalmaterials. This is accordingly also based on a relatively longillumination time of 60 seconds. Furthermore, the LED should bepositioned at a distance of 7 mm±2 mm from the material to be hardened.This means that the LED is located in the patient's mouth. Even if theLED is encapsulated in a housing, adequate hygiene is impossible, as isnormally achieved by means of sterilization at temperatures of about130° C., since these high temperatures could destroy the LED. For thisreason, optically conducting elements such as fiber-optical waveguideshave been introduced as standard for irradiation appliances forhardening dental materials. These can be removed from the housing, andsterilized, after the treatment.

It has been found that light beams can be injected into a fiber-opticalwaveguide largely without losses only when they strike the inlet area ata specific angle, which is less than or equal to the so-calledacceptance angle.

This acceptance angle is typically ±30°. The possible LEDs emit light,however, in a cone whose aperture angle is in some circumstances greaterthan this maximum injection angle. Only some of the power can thereforebe used when the LED is arranged directly in front of the opticalwaveguide.

However, owing to the wide aperture angle of LEDs (for example ±50° ormore), lenses are suitable only to a restricted extent for increasingthe injection efficiency. Although such lenses can be used to deflectand inject some of the beams whose angles are greater than theacceptance angle, at the same time, however, the efficiency of theinjection process for the beams which could intrinsically be injecteddirectly falls, for example, as a result of reflection losses, sincethese beams also have to pass through the lens.

Direct injection of the beams which are emitted within the acceptanceangle of, for example, the LED, that is to say without having previouslybeen focused by refractive or reflective optical elements, would beparticularly advantageous since there would then be no need to acceptany losses whatsoever as a result of radiation refraction or focusing.

On the other hand, optical elements are required in order to make itpossible to use the beams emitted outside the acceptance angle, as well.

In summary, all known embodiments of high-power light appliances usecomplex arrangements of a greater or lesser number of light-emittingelements in order to achieve intensities which are as high as possible.The greater the number of individual elements in this case, the morecomplex and at the same time the more lossy the required opticalelements or arrangements which are necessary in order to gather andfocus the light from the individual elements. However, if only a smallnumber of light-emitting elements, or only one light-emitting element,are or is used, then either the radiation power is low or other seriousdisadvantages must be accepted, such as lack of hygiene or short life.

In consequence, one object of the present invention is to provide anirradiation appliance having as few light-emitting units as possible,which is simple to manufacture but has a light power which is comparableto or better than that of appliances with LED arrays.

A further object is to provide an irradiation appliance by means ofwhich light-hardening dental filling materials can be hardened morequickly and reliably.

Finally, the reduction in the space that is required for thelight-emitting unit and the rechargeable battery that is required isintended to reduce the size of the appliance, not least making itpossible to reduce the production costs.

Furthermore, the light-emitting unit should have a long life. Simplecleaning of the appliance is also desirable, as can be achieved withnormal optical waveguides.

This object is achieved by an irradiation appliance as is described inthe claims.

The expressions “contain” and “comprise” for the purposes of theinvention introduce a non-exclusive enumeration of features. Similarly,the expression “a or one” should be understood in the sense of “at leastone”.

It has been found that higher efficiency and a higher radiation yieldwith reduced complexity and less space being required can be achieved bythe provision or installation of a reflector element which is arrangedas selective combining optics between a light-emitting andlight-receiving unit.

This takes account of the fact that a considerable proportion of thelight from, for example, one LED is emitted such that it can be injecteddirectly into an optical waveguide. These beams are not intended to beinfluenced by the selective combining optics or the reflector element,since this would generally be associated with attenuation. Only thosebeams whose tilt angle with respect to the optical axis is greater thanthe acceptance angle are intended to be deflected in this way anddeflected in the direction of the opening in the optical waveguide, suchthat they can be injected.

It has been found that neither the directly injected beams nor thedeflected beams allow satisfactory light conduction. Adequateperformance of the irradiation appliance is guaranteed only by optimumuse of both components in total, as is possible by means of thearrangement according to the invention.

The reflector element extends over the entire distance from the emissionsurface of the light-emitting element to the inlet surface of thelight-receiving element. The expression “the entire distance” does not,however, mean that there must be no variation whatsoever between thereflector element and the light-receiving element, as may be caused, forexample, by design and manufacturing factors. However, in any case, thevariation should be minimized.

This includes any variation caused by manufacturing or design in thetransition from the outlet surface of the reflector element to the inletsurface of the light-receiving element which, for example, allows theattachment or fitting of an optical waveguide. A small gap is alsopossible between the outlet surface of the reflector element and theinlet area of the light-receiving unit, into which a thin glass panel isintroduced. This is used to protect the sensitive reflector surfaceagainst dirt. The glass panel ideally has optical blooming on both sidesin order to avoid radiation losses resulting from reflections.

A suitable reflector element has, for example, a conical shape and ishollow internally, that is to say it is not filled with a refractivemedium in the optical sense.

The reflector element is preferably in the form of a truncated conicalsurface which faces at least the light-emitting element and is mirroredon the inside. The smaller cross-sectional area of the cone in this casefaces the light-emitting unit.

The light-emitting unit is arranged at a distance in front of thelight-receiving element such that the proportion of the light beamswhich can be injected directly (that is to say light beams at anglesless than or equal to the acceptance angle) completely illuminates theinlet area.

This represents the optimum arrangement for this proportion of the lightcone, since, in this case, no losses occur as a result of refraction,diffraction or boundary surface transitions at any optical elementswhatsoever. In the case of fiber-optical waveguides, this generallymeans that the distance to the light-emitting unit is somewhat greaterthan or equal to half the diameter of the inlet opening of thelight-receiving unit.

The truncated conical surface which is defined by this arrangementbetween the light-emitting unit and the light-receiving element is thus,according to the invention, bounded by a reflector element. Thisreflector element opens from the diameter of the light-emitting unit tothat of the light-receiving unit, so that the angle of the cone isdefined by the distance from the light-emitting unit to thelight-receiving unit.

By adaptation of the cross section of the inlet opening of thelight-receiving unit, it is thus possible to achieve specific angles inorder to select an optimum arrangement for the respective embodiment ofthe light-emitting unit.

All beams which have an emission angle that is greater than theacceptance angle strike the reflector element, where they are reflected,with the angle with respect to the optical axis now being reduced bytwice the reflector element angle.

If, for example, a light beam at an angle of 50° with respect to theoptical axis strikes the reflector element with an opening angle of 10°,then, after reflection, its angle is −30°, this being the angle at whichit strikes the optical waveguide, and can now be injected.

The reflector element preferably has the following features for thispurpose:

The inlet opening of the reflector element is sufficiently large thatall of the beams which are emitted from the light-emitting unit can bereceived, that is to say it is generally of the same size as the LEDlens that is used.

The outlet opening of the reflector element has approximately the samediameter as the inlet opening of the light-receiving element.

The aperture angle of the reflector element follows the relationship:inclination angle=0.5×(maximum beam angle−acceptance angle).

In addition, the inclination angle can also decrease from higher valuesat the start (close to the light-emitting unit) to smaller values, sincethe beams which are reflected at the start have a higher tilt angle thanthose close to the optical waveguide.

The maximum beam angle is predetermined by the emission characteristicof the light-emitting unit and characterizes the beams which are stillintended to be used for irradiation of the treatment point. Beams withan even greater angle are either not emitted or are emitted only with anegligible intensity from the light-emitting element, so that their usewould not contribute to significantly increasing the intensity.

By way of example, commercially available high-power diodes emit 30% ofthe total intensity within the acceptance angle of normal opticalwaveguides of ±30°, a further 60% in an angle range between 30° and 50°,and the remaining 10% at emission angles between 50° and 90°. Sincetheir use would produce a small amount comparable to the 30° to 50°range, the maximum beam angle is sensibly set at 50° in this example.

The maximum beam angle may thus, for example, be about 65°, preferablyabout 55°, and particularly preferably about 50°.

The light-emitting units which are used preferably have a life of manyhundred hours, and preferably more than 1000 hours, emit in a range from400 to 500 nm, have an emission maximum between 440 and 480 nm and havea light power of at least 100 mW, preferably at least 200 mW.

The irradiation appliance is distinguished, inter alia, by the followingfeatures:

It preferably has only one reflector element and has no furthercombining optics, which operate in a reflective or refractive manner, inthe area between the light-emitting unit and the inlet opening of thelight-receiving unit.

It preferably has no active cooling elements operated by means ofelectrical power.

It can preferably be operated independently of the mains system.

A polished metal body composed, for example, of aluminum, titanium orstainless steel may be used as the reflector element material, as wellas metal sheets with good reflection characteristics, mirroring layersor else, for example, metal-free interference mirror sheets such asthose known from WO 00/07044 and available, for example, from 3M.

For the purposes of the invention, a light-emitting unit is any compactform of radiation source which produces light, preferably at awavelength in the range from 400 to 500 nm. This emission is preferablydirectional and can be achieved by means of optical elements which areintegrated in the light-emitting unit, such as those normally used forhigh-power light-emitting diodes. The internal configuration of the unitis in this case irrelevant, irrespective of whether it comprises asingle light-emitting element, or a combination of two or morelight-emitting elements.

In particular, the term light-emitting unit includes light-emittingdiodes (LEDs). However, it is also possible to use laser diodes, such asthose described in EP 0 755 662 A.

A light-receiving unit for the purposes of the invention is anyapparatus which has the capability to receive and to re-emitdirectionally light which is produced by the light-emitting unit or thelight-emitting elements.

These are normally so-called optical waveguide rods, which comprise alarge number of bundled glass fibers. These optical waveguide rods canbe reversibly connected to the light-emitting unit, or to the housingwhich contains it, via a coupling or a thread.

However, this also includes conventional filter disks, scattered-lightdisks or optical waveguide converters, such as those described in DE 10006 286 C1.

If required, the light-emitting unit and/or the reflector element is/arecovered with a transparent disk, in order to protect the light-emittingunit and/or the reflector element against moisture and dirt when theoptical waveguides are removed.

The light-emitting unit is preferably mounted on a normally flat panel.

The problem of dissipating the heat which is produced by thelight-emitting element during operation of the irradiation appliance canbe solved by the use of thermally highly conductive board materialand/or direct thermally conductive attachment of the element to a heatsink. The heat is in this case passed to the appliance housing bythermal conduction, from where it is radiated away to the environment.There is therefore no need to use active cooling elements, such as fansor Peltier elements, which consume additional power and, in the case ofa fan, produce a high noise level. Furthermore, a further improvement inhygiene is achieved, since no ventilation slots need be provided, sincethese are difficult to keep clean.

In order to entrap the amount of heat that is produced during normalshort-term operation, and thus to keep the temperature of thelight-emitting unit low, which lengthens the life, an additional elementwith a high thermal capacity can be thermally connected to thelight-emitting unit. This stores the amount of heat produced duringoperation, and emits it continuously to the environment via thethermally highly conductive housing during pauses in treatment.

The irradiation appliance normally also has an electronic control unitfor controlling the voltage and current level for the light-emittingelement, a storage unit for electrical energy, such as batteries orrechargeable batteries, preferably lithium-ion, NiMH or Ni/Cdrechargeable batteries, a display unit and a housing.

The housing is preferably designed such that it essentially has asurface without any gaps, in which the display unit is integrated.

The illumination appliance according to the invention is used inparticular in the medical field, preferably in the dental field, and mayon the one hand be used to illuminate the treatment point or toirradiate substances which can be cured by light, in particular dentalfilling materials, such as composites, compomers or glass ionomercements.

During use, the outlet end of the optical waveguide rod is pointed atthe treatment point, for example at a tooth filling to be hardened, andthe switch-on pushbutton is pressed, thus activating the LED and at thesame time switching on the display unit. After a predetermined orvariable time interval, the control circuit switches off the powersupply to the light-emitting diode and to the display unit.

In one embodiment, the irradiation appliance has a reflector elementwherein the length of the reflector element may be greater than thedistance between the light-emitting unit and the light-receiving unit.The reflector element may be a truncated cone which may be reflective onthe inside and the larger opening in the reflector element may becovered by an optical protective glass. The inner surface of thetruncated cone may be metallically mirrored or may be formed from asheet with high optical reflection. The sheet may be a metal-free,multilayer interference reflector sheet. The light-emitting unit may bea blue high-power light-emitting diode, with at least one light-emittingelement whose size may be at least 0.25 mm², and the unit may produce aradiation power between 100 and 1400 mW. Alternatively, the at least onelight-emitting element size may be between 1 and 5 mm², and theradiation power between 200 and 800 mW. The housing of the irradiationappliance may be composed entirely or partially of a material of highthermal conductivity and thermal capacity and the housing may becomposed entirely or partially of aluminum, zinc or brass. Thelight-emitting unit may also be thermally connected to an element havinga thermal capacity between 10 and 100 Joule/Kelvin, or preferablybetween 20 and 50 Joule/Kelvin. The light-receiving element may beselected from a rigid optical waveguide rod or a flexible opticalwaveguide.

In another embodiment, the reflector element may selectively deflectonly those light beams whose emission angel from the light-emitting unitis greater than the acceptance angel of the light-receiving unit in adesired inlet angle range into the light-receiving unit, but may leaveother light beams unaffected.

Preferred exemplary embodiments will be explained in the following textwith reference to the drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a longitudinal section through an irradiation appliance.

FIG. 2 shows a longitudinal section through an irradiation appliance inthe area of the transition from the light-emitting element to thelight-receiving element, without a reflector element.

FIG. 3 shows a longitudinal section corresponding to that shown in FIG.1, with a reflector element in the form of a cone.

DETAILED DESCRIPTION OF THE INVENTION

The handheld appliance shown in FIG. 1 for irradiation of dentalplastics contains a light-emitting unit (11), with a light-emittingelement in the form of an LED chip (12), in the front area of anessentially cylindrical housing (10).

The light-emitting element (12) is fed from a battery (13), which isarranged in the rear part of the housing (10), via a driver stage (14)which is time-controlled by a control circuit (15). The control circuit(15) is connected to a switch-on pushbutton (16), which is arranged onthe side of the housing (10), and to a display diode (17), which islikewise arranged on the side of the housing (10). A light-receivingunit (18) in the form of an optical waveguide rod, whose front end iscurved, projects out of the front conical end of the housing (10). Thelight-emitting element (12) is located on a flat holding plate (19).

FIG. 2 shows which of the beams which are emitted from thelight-emitting element (12) can be injected, for example, into anoptical waveguide (18), and which cannot. The beams which are symbolizedby a solid line can be injected into the optical waveguide while, incontrast, the beams illustrated by dashed lines cannot be injected intoit, since their angle with respect to the optical axis is greater thanthe acceptance angle of the optical waveguide.

FIG. 3 corresponds essentially to FIG. 2, with the difference that areflector element (22) in the form of a mirrored truncated conicalsurface extends from the surface of the light-emitting unit (12) to theinlet surface of the optical waveguide (18). By virtue of this reflectorelement, those beams which otherwise cannot be injected into the opticalwaveguide because of their angle, which is greater than the acceptanceangle of the optical waveguide, can also, however, in the end beinjected, since the magnitude of their tilt angle with respect to theoptical axis is reduced by twice the reflector aperture angle, as aconsequence of reflection. Those beams which are emitted from thelight-emitting unit within a light cone with angles less than theacceptance angle directly illuminate the inlet opening of the opticalwaveguide, so that their intensity can be made use of as well aspossible.

LIST OF REFERENCE SYMBOLS

-   10 Housing-   11 Light-emitting unit-   12 Light-emitting element/light-emitting diode-   13 Battery-   14 Driver stage-   15 Control circuit-   16 Switch-on pushbutton-   17 Display unit-   18 Light-receiving unit/optical waveguide rod-   19 Holding plate-   20 Focus range-   21 Heat sink body-   22 Reflector element-   23 Optical protective glass

1. An irradiation appliance, having: a housing; a single light-emittingunit which is arranged in the housing; a light-receiving unit comprisingan optical wave guide and having an inlet opening; and a reflectorelement having an inner surface in the shape of a truncated cone,wherein the reflector element extends over the entire distance betweenthe light-emitting unit and the inlet opening of the light-receivingunit and has a smaller and a larger opening; and wherein the smalleropening faces the light-emitting unit, and the larger opening faces thelight-receiving unit.
 2. The irradiation appliance as claimed in claim1, wherein the larger opening has a diameter that is less than or equalto that of the light-receiving unit.
 3. The irradiation appliance asclaimed in claim 1, wherein the smaller opening at least partiallysurrounds the light-emitting unit.
 4. The irradiation appliance asclaimed in claim 1, wherein the reflector element has an aperture anglethat decreases in size from the smaller opening to the larger opening.5. The irradiation appliance as claimed in claim 1, wherein the distancebetween the light-emitting unit and the light-receiving unit is greaterthan half the diameter of the light-receiving unit.
 6. The irradiationappliance as claimed in claim 1, wherein the length of the reflectorelement is greater than the distance between the light-emitting unit andthe light-receiving unit.
 7. The irradiation appliance as claimed inclaim 1, wherein the larger opening in the reflector element is coveredby an optical protective glass.
 8. The irradiation appliance as claimedin claim 7, wherein the optical protective glass has blooming on one orboth faces.
 9. The irradiation appliance as claimed in claim 1, whereinthe reflector element is reflective on the inside.
 10. The irradiationappliance as claimed in claim 9, wherein the inner surface of thetruncated cone is metallically mirrored or is formed from a sheet withhigh optical reflection.
 11. The irradiation appliance as claimed inclaim 10, wherein the sheet is composed of a metal with good reflectioncharacteristics, or is coated with such a metal.
 12. The irradiationappliance as claimed in claim 10, wherein the sheet is a metal-free,multilayer interference reflector sheet.
 13. The irradiation applianceas claimed in claim 1, wherein the light-emitting unit is a bluehigh-power light-emitting diode, comprising at least one light-emittingelement whose size is at least 0.25 mm², and the unit produces aradiation power between 100 and 1400 mW.
 14. The irradiation applianceas claimed in claim 13, wherein the at least one light-emitting elementsize is between 1 and 5 mm², and the radiation power is between 200 and800 mW.
 15. The irradiation appliance as claimed in claim 1, wherein thelight-emitting unit is thermally connected to the housing.
 16. Theirradiation appliance as claimed in claim 15, wherein the housing iscomposed entirely or partially of a material of high thermalconductivity and thermal capacity.
 17. The irradiation appliance asclaimed in claim 16, wherein the housing is composed entirely orpartially of aluminum, zinc or brass.
 18. The irradiation appliance asclaimed in claim 16, wherein the light-emitting unit is additionallythermally connected to an element having a thermal capacity between 10and 100 Joule/Kelvin.
 19. The irradiation appliance as claimed in claim18, wherein the thermal capacity is between 20 and 50 Joule/Kelvin. 20.The irradiation appliance as claimed in claim 1, wherein thelight-emitting element is mounted on a planar holding plate of highthermal conductivity.
 21. The irradiation appliance as claimed in claim1, wherein the light-receiving element is selected from a rigid opticalwaveguide rod or a flexible optical waveguide.
 22. An irradiationappliance, having: a housing; a single light-emitting unit which isarranged in the housing; a light-receiving unit comprising an opticalwave guide and having an inlet opening; and a reflector element whichextends over the entire distance between the light-emitting unit and theinlet opening of the light-receiving unit and has a smaller and a largeropening; wherein the smaller opening faces the light-emitting unit, andthe larger opening faces the light-receiving unit; and wherein theinclination angle ν of the reflector element follows the relationship:ν=0.5×(δ−α) where δ is a maximum emission angle at which light beamsintended to be injected into the optical waveguide leave thelight-emitting unit, and α is an acceptance angle of the opticalwaveguide.